XR400R Head

I disassembled the top end of my XR400R this week getting ready for the machine work I have planned. When I took the valve cover off and removed the cam I found that the cam saddles had what looks like scuffing. The saddles are still smooth and you can't catch your fingernail on any of the scuff marks. Does this look like it's acceptable to continue running the head. Just looking for opinions. I have included some pics.  I'm taking the head to the machine shop tomorrow to drop off for a valve job so I'll be able to ask machinist as well. Thanks.



the cam should be mainly supported by the end 2 roller bearings, but i note you have a little scuffing there too suggesting the roller is turning in the housing. you could put a smear of bearing seal there when you reassemble it.

not sure about the middle ones, i'd get the cam checked for straightness which the machine shop can do with some v blocks and a dial gauge.




Not unusual on an RFVC head, practically every head I have removed that had a lot of use on it had the scuffing. I have installed heads that were  worse than yours with no problems. I suggest that you replace the bearings. 

It's fine don't worry abouf it.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now